The HYGIA study was designed to investigate, first, the comparative prognostic value of several BP parameters (including, among many others, BP variability, the diurnal/nocturnal ratio, diurnal and nocturnal means, hyperbaric index, slope of morning rise, etc) in the prediction of vascular, metabolic, and renal morbidity and mortality; second, whether potential changes in the circadian BP pattern after treatment with hypertension medications may be associated to changes in the risk of cardiovascular events, stroke, diabetes, and/or chronic kidney disease; and third, in keeping with the second major objective above, to further assess the potential changes in efficacy, safety profile, and/or capability of hypertension medications, used either alone or in combination, to modulate the circadian BP pattern and to reduce vascular, metabolic, and renal risks as a function of the circadian time of administration.